Over the years, a wide variety of different couplings have been developed for conduits, pipes and the like. These couplings have typically taken the form of mechanical couplings that are either rigid or semi-rigid in form, especially where there is a requirement that the coupling be leak-proof in applications where the conduit or pipe carries a liquid or gas therethrough. With such mechanical couplings, it has been commonplace to utilize a seal that is in contact with each of the adjoining ends of the conduit or pipe.
While the design of such couplings and seals has evolved to a significant extent, there exists certain applications where conventional rigid or semi-rigid mechanical couplings are not suitable. This is the case, for instance, whenever two conduit or pipe sections must be joined in a leak-proof manner while at the same time permitting some degree of relative movement therebetween. For this purpose, conventional mechanical couplings have not proven to be useful since they cannot accommodate the relative movement between the two conduit or pipe sections.
Unfortunately, conventional flexible couplings also may not be suitable for every application where a leak-proof connection is necessary between two relatively movable conduit or pipe sections. Most typical flexible couplings have taken the form of a sleeve of a flexible material such as rubber or the like, and there are many applications in which the conduit or pipe sections must carry a high temperature fluid or a fluid having corrosive or other deleterious characteristics. In these cases, it is difficult, if not impossible, to select a material for the conventional flexible coupling that is capable of withstanding the extreme environmental characteristics of the fluid.
Since the fluid would normally be in contact with the conventional flexible coupling through a gap between the ends of the two conduit or pipe sections, this problem is known to be especially critical for those applications in which the ends of the conduit or pipe sections must accommodate some degree of relative movement therebetween.
In one particular application, a pressurized gas is transferred from a stationary source to a vibrating chamber through a gas-carrying conduit or pipe. This application is one in which the vibrating chamber may comprise an integral portion of a vibratory fluidized bed that is utilized to reclaim foundry sand by burning off the binder. The gas-carrying conduit or pipe typically will include a first conduit or pipe section having both an upstream end connected to the stationary source for the pressurized gas and a spaced coupling end. The gas-carrying conduit or pipe will also include a second conduit or pipe section having both a second coupling end near the first coupling end of the first conduit or pipe section and a spaced downstream end connected to the vibrating chamber. This application typically utilizes pressurized air that is heated to a temperature of at least 600.degree. F. and is delivered to the vibrating chamber for fluidizing sand in the vibratory fluidized bed. Due to the relative movement of the conduit or pipe sections caused by the vibrating motion, there must exist a gap between the first and second coupling ends thereof.
For this application, a conventional flexible mechanical coupling will be understood to present a problem in view of the high temperature of the pressurized air. There must necessarily be a way to accommodate the relative movement between the first and second coupling ends of the conduit or pipe sections, thereby requiring the gap therebetween, but this means that either the material of the flexible mechanical coupling must be such as to withstand the high temperature of the pressurized air, or the flexible mechanical coupling must be isolated from exposure to the hot pressurized air. In either case, any solution in the form of a conventional flexible mechanical coupling has quite necessarily been understood to be complex and expensive.
The present invention is directed to overcoming one or more of the foregoing problems while achieving one or more of the resulting objects by providing a unique mechanical leak-proof coupling.